Title :
High-Index-Layer Coating on a Lensed Fiber Endface for Enhanced Focusing Power
Author :
Shiraishi, Kazuo ; Kawasaki, Nobuyuki ; Yoda, Hidehiko ; Watanabe, Kenji ; Umetsu, Masato ; Hitomi, Tetsuya ; Muro, Koichi
Author_Institution :
Grad. Sch. of Eng., Utsunomiya Univ., Utsunomiya
fDate :
4/1/2009 12:00:00 AM
Abstract :
A new scheme for lensed fibers with a high focusing power is proposed. The new lensed fiber has a high-index layer coated (HILC) on a convex-shaped endface of a single-mode fiber (SMF). Numerical investigation shows that, by coating a 10-mum-thick film with refractive index of 3.7, the lensed fiber can contract the beam diameter of the propagating mode from 10.4 mum at the wavelength of 1.55 mum, to 1.2 mum. The enhanced focusing effect of the lensed fiber has been confirmed experimentally by coating an a-Si:H film on the lensed endface. The measured focused spot diameter was as small as 1.6 mum, much the same as the wavelength.
Keywords :
coatings; elemental semiconductors; hydrogen; lenses; optical fibres; refractive index; semiconductor thin films; silicon; Si:H; enhanced focusing power; high-index-layer coating; lensed fiber endface; refractive index; single-mode fiber; size 10 mum; wavelength 1.55 mum to 1.2 mum; Coatings; Integrated optics; Optical fiber devices; Optical fibers; Optical films; Optical refraction; Optical variables control; Optical waveguides; Refractive index; Stimulated emission; Lenses; optical fiber connection; optical fiber devices; optical fibers; semiconductor lasers; spot size;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2008.927772
